Since the development of the integrated circuit (IC), the semiconductor industry has sought to continue to improve the performance or size of the IC. Many of these improvements have focused on smaller feature sizes so that the speed of the IC can be increased. By decreasing the feature sizes, the density of devices (e.g., transistors, diodes, resistors, capacitors, etc.) on the IC has increased. By increasing the density, distances between devices generally decreases, which allows for a smaller resistance and capacitance between devices. Thus, a resistance-capacitance (RC) time constant can be decreased.
Other improvements have focused on using dissimilar materials to achieve beneficial results. Epitaxial growth of dissimilar materials in a substrate has been used to gain beneficial results. For example, the growth of a dissimilar material on a substrate can advantageously introduce stresses and strains in materials to increase the mobility of a charge carrier. Further, the electrical characteristics of an epitaxially grown material, such as a dopant in the material, can be used to gain better a better crystal structure while having a dopant ion to decrease a resistance or increase mobility.
However, epitaxial growth of a material may result in faceting. The faceting may be a problem when etching an opening to the material to form a contact in the opening. If the opening is slightly misaligned, such as over a facet, the opening may not be etched to the epitaxial material. If the opening is not etched to the facet, the conductive material of the contact will not make physical contact with the facet. Hence, the contact may not contact the facet resulting in an open contact.